Chevrolet 10 Series 1970, Service Manual

Page: 19 / 671

LUBRICATION 0-17
high speeds, the lubricant should be changed e v e ry 12,000
m ile s . It may be n ecessary to change lubricant m ore
often i f v e h icle is used o ff road in dusty a rea s.
POSITRACTION
Same as standard axle but use only the special P o s i-
tra ction lubricant.
TWO-SPEED AXLES
The shift unit should be fille d with lubricant to the f i l ­
le r opening on the front c o v e r using re frig e ra tio n m a­
chine o il. The o il le v e l should be checked e v e ry 12,000
m ile s o r 3 months, w h ichever occu rs fir s t.
PROPELLER SHAFT SLIP JOINTS
P r o p e lle r shaft slip joints should be lubricated e v e ry
6,000 m ile s with w ater resistan t E P chassis grea se
which m eets G eneral M otors S pecification s #GM 6031M.
UNIVERSAL JOINTS
U n iversa l joints equipped with lubrication fittin gs
should be lu bricated e v e ry 6,000 m ile s with w ater r e ­
sistant E P chassis g re a s e which m eets G eneral M otors
Specification #GM 6031M.
M ore frequent lu brication may be requ ired on heavy
duty " O f f the Road’ ' operations.
FOUR WHEEL DRIVE
M ost lu brication recom m endations and proced u res fo r
4 wheel d rive-equ ip p ed trucks a re the same fo r c o r r e ­
sponding components o f conventional d riv e trucks. Only
the front axle, including the d iffe re n tia l, the tra n sfer
case, which tran sm its pow er fro m the tran sm ission to
eith e r front o r r e a r axles, and associated linkage points
and a ir vents req u ire sp ecial p roced u res.
FRONT AXLE
The front axle should be checked e v e r y 6,000 m ile s and
r e fille d with S .A .E . 90 “ M u lti-P u rp o s e ” G ear Lubricant
when n ecessa ry. W ith the d iffe re n tia l at operating te m ­
p era tu re, f ill to the le v e l o f f i lle r plug hole. If d iffe re n ­
tia l is cold, f ill to le v e l o f 1/2" below the f i lle r plug
hole. Capacity: 5 pt.
A ir V en t Hose
Check vent hose fo r kinks and p ro p er installation e v e ry
6000 m iles.
TRANSFER CASE
Check the tra n s fe r case le v e l e v e ry 6,000 m iles and, if
n ecessa ry , add lubricant to b rin g to the le v e l o f the f ille r
plug hole. Use SAE “ M u lti-p u rp ose” G ear Lubricant,
m eeting requ irem en ts o f U.S. Ordinance Spec. M IL - L -
2105B and fo llo w the “ G ear Lubricant V is c o s ity T a b le ”
fo r p rop er v is c o s ity “ M u lti-P u rp o s e ” gea r lubricant to
be used during veh icle operation.
CONTROL LEVER A N D LINKAGE
Since no g rea se fitting is provid ed in the control le v e r
it is n ecessary to brush o r spray engine o il on the le v e r
pivot point and on a ll exposed control linkage e v e ry 6,000
m ile s .
BRAKES
PARKING BRAKE
E v e ry 6,000 m ile s clean and lu bricate a ll parking brake
p ivo t points with w ater resistan t E P chassis gre a s e which
m eets G eneral M otors Specification #GM 6031M.
HYDRAULIC BRAKE SYSTEM
The s e rv ic e brake and parkint brake system s are de­
signed fo r braking p erform an ce under a wide range o f
d riv in g conditions even when the veh icle is loaded to its
full rated veh icle load.
CA UTIO N: D rivin g through deep w ater may
a ffect brake perform an ce. T o assu re norm al
operation a fte r being wetted, s e r v ic e brakes
must be d ried . T o dry them quickly, lightly
apply the b rakes while maintaining a slow f o r ­
ward speed until brake perform an ce returns to
norm al.
The s e r v ic e brakes on veh icles equipped with a split
system a re designed so that in the event o f a hydraulic
fluid leak in on e-h a lf o f the sytem , the other half s till
p ro vid es braking action. A brake system warning light
is located in the instrum ent clu ster. The function o f this
light is to indicate a malfunction in the reg u la r braking
system . In the event o f broken brake lin es, m a jor brake
fluid loss, a ir in the brake lin es or a p ressu re deviation
between the front and the re a r wheel brake lin es, the
light w ill com e on and stay on while braking. In this
event, the veh icle should not be driven until the cause has
been determ ined and, i f n ecessary, co rre c te d .
V e h icles equipped with pow er brakes use engine v a c ­
uum to reduce the braking e ffo rt. The system has a
vacuum re s e r v e which w ill supply two o r m ore pow er
assisted brake applications a fter the engine has stopped.
A fte r the vacuum r e s e r v e has been exhausted, the veh icle
can s till be stopped by using g rea ter pedal fo rc e .
The C h evrolet braking system re q u ire s v e r y little
ca re; how ever, the system should be checked o ccasion ­
a lly fo r indications o f fluid leak. If leaks a re found the
n ecessary r e p a irs should be made at once. Keep the
brakes p ro p e rly adjusted. Check a ll vacuum hose con­
nections fo r leakage.
M aster C ylinder
Check m aster cylin d er fluid le v e l in both r e s e r v o ir s
e v e ry 6,000 m ile s . If the fluid is low in the r e s e r v o ir ,
it should be fille d to a point about 1/4" fro m the top r e a r
o f each r e s e r v o ir with G .M . Supreme No. 11 H ydraulic
Brake Fluid o r equivalent.
Inspection of Brake Lining
CA UTIO N: Brake linings should be p e rio d ic a lly
inspected fo r w ea r. The frequency o f this in­
spection depends upon d rivin g conditions such
as tra ffic o r te rra in , and also the d rivin g tech­
niques o f individual custom ers.
CHEVROLET TRUCK SERVICE MANUAL